The Model S was first introduced in the US in 2012, ever since Tesla has just been refining the formula

In 2013 it paid back every dollar it owed to the US government and became the top-performing business on the New York Stock Exchange’s Nasdaq 100 index.

It expects to deliver close to 90,000 new cars this year and an ambitious 500,000 a year by the end of the decade.

Meanwhile, Tesla has been making incremental improvements to the car with which it blazed a trail three years ago when it set about proving that the electrically powered luxury car’s time had come.

Since our 2013 road test, the remarkable Model S has been in receipt of more power and performance (neither of which it really needed), more battery capacity and cruising range, a second front-mounted electric motor and consequent four-wheel drive capability and a new Autopilot feature that extends beyond the abilities of most car makers’ lane keeping and active cruise controls.